HOW DO you measure the amount of fuel a satellite or space probe has left?
Earthbound methods are non-starters in zero gravity. Now engineers at satellite
maker Lockheed Martin in California and at Purdue University in Indiana have
found a way. Knowing exactly what you’ve got left will extend a craft’s useful
life, they say, saving satellite operators millions of dollars.
Their trick is to use a computer program that models the surface tension of
hydrazine fuel. This should give them a better idea of how hydrazine behaves
inside the satellite’s fuel tank. “In automobiles, we have a float that’s…
